1. Field of the Invention
A dual function lock/latch device selectively operable in a latch configuration or lock configuration to permit use as a latch or lock.
2. Description of the Prior Art
U.S. Pat. No. 3,875,773 discloses is a lock comprising a housing including a primary spline, secondary spline and trapping spline formed on the inner surface thereof and a plug including a keyway rotatably retained in the housing. A primary tumbler projects from the plug to interact with the primary spline to selectively retain the lock in an unlocked position and to interact with the secondary spline to selectively retain the lock in a locked position. A trapping tumbler projects from the plug to selectively retain the plug in the locked position by interacting therewith.
U.S. Pat. No. 1,141,463 shows a cylinder lock comprising a casing having a plug including a keyway rotatably disposed therein. A plurality of keys are provided to rotate the plug. A first cam including a key slot is fixedly connected to the plug. A second cam carrier by and rotating with the first cam is movable between at least three positions relative thereto. Means normally hold the second cam in one of the positions. The second cam including at least two spaced abutments is normally aligned with the key slot arranged to engage several of the keys such that the second cam is movable into the second and third positions.
U.S. Pat. No. 1,334,292 discloses a lock comprising a shell having locking pins adapted to be retired therein. A keyway member is rotatably mounted in the shell having plungers adapted to retire the locking pins when aligned therewith and engaged by a key and an auxiliary means to permit axial movement of the plungers by the key when the plungers and locking pins are placed out of alignment subsequent to a rotative movement of the keyway member. The auxiliary means consisting of a series of pins disposed at an inclination relative to the locking pins.
Additional examples of the prior art are shown in U.S. Pat. Nos. 1,207,123; 1,233,806; 1,608,080 and 2,754,673.